This invention relates to nonwoven fabrics well adapted to embossing and suitable for use as water-absorbent kitchen papers, wipe-out sheets, etc. as well as a method for making such nonwoven fabric.
It is well known to emboss/deboss nonwoven fabrics comprising a mixture of thermoplastic synthetic fibers having a fineness of 1xcx9c10 d and thereby to form an emboss/a deboss pattern thereon so that the nonwoven fabric may be used as water-absorbent kitchen papers or wipe up sheets.
However, it is not necessarily easy to form irregularities thereon by embossing the kitchen papers or the like of the prior art because the synthetic fiber has relatively high rigidity and elasticity. This is true particularly when it is desired to form fine or distinctly contoured embosses/debosses.
When it is attempted to feed a web of nonwoven fabric through an embossing machine and thereby to obtain kitchen papers formed with apertures each having a diameter in order of 5 mm or less, individual fibers may often extend from the aperture periphery into this aperture, resulting in the indistinctly contoured aperture. Probably, it is for the reason that the individual fibers can not be smoothly rearranged around each of projections provided on the embossing machine sufficiently to form the desired distinctly contoured aperture. The smaller a diameter of the aperture and/or the larger a basis weight of a nonwoven fabric is, the greater this problem becomes. While it is obvious that the individual fibers extending into the aperture lead to a substantial reduction of the aperture""s diameter, a degree of such reduction is not necessarily uniform. This makes a proper design of the aperture difficult. Accordingly, it is required for nonwoven fabric used as material for kitchen papers or the like to have a sufficiently high formability to facilitate formation of embosses/debosses or apertures.
In view of the problem as has been described above, it is an object of the invention to provide a nonwoven fabric having a sufficiently high formability to facilitate formation of embosses/debosses or apertures when such nonwoven fabric is intended to be used as material for kitchen papers or the like, on one hand, and to provide a method for making such nonwoven fabric.
According to a first aspect of the invention, there is provided a nonwoven fabric containing thermoplastic synthetic microfibers, the nonwoven fabric comprising synthetic microfibers being 5xcx9c30 mm long and as fine as of 0.1xcx9c0.8 d, in 90xcx9c10% by weight, mixed and mechanically entangled with pulp fibers being 2xcx9c7 mm long, in 10-90% by weight, so as to have a basis weight of 10xcx9c80 g/m2 as a whole.
According to the first aspect of the invention, melt blown fibers are preferably selected as the thermoplastic synthetic fibers.
According to a second aspect of the invention, there is provided a method for making a nonwoven fabric containing thermoplastic synthetic microfibers, the method comprising the steps of:
a. obtaining a wet sheet from slurry containing 0.5xcx9c20% by weight of a fibrous mixture dispersed in water, the fibrous mixture comprising thermoplastic synthetic fibers being 7-30 mm long and as fine as of 0.1xcx9c0.8 d, in 90xcx9c10% by weight, mixed with pulp fibers being 2xcx9c7 mm long, in 10xcx9c90% by weight; and
b. placing the wet sheet on a support and then subjecting the wet sheet to high velocity water jet streams of 50-200 kgf/cm2 for mechanically entangling the fibrous mixture.
According to the second aspect of the invention, melt blown fibers are preferably selected as the thermoplastic synthetic fibers.